Imaging device and camera

ABSTRACT

A camera body includes an imaging unit, a reflecting mirror, a determination unit, and a mirror controller. The imaging unit is configured to convert the optical image into an image signal and acquires an image of the subject. The reflecting mirror has a first state of being in the optical path of the optical system and a second state of being outside the optical path. The mirror controller is configured to retract the reflecting mirror to outside the optical path of the optical system when the reflecting mirror is in the first state of being in the optical path of the optical system and a moving picture photography mode is selected, which is a mode for capturing moving pictures.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Patent ApplicationNo. PCT/JP2008/002299 filed on Aug. 25, 2008. The entire disclosure ofInternational Patent Application No. PCT/JP2008/002299 is herebyincorporated herein by reference.

This application claims priority to Japanese Patent Application No.2007-222395. The entire disclosure of Japanese Patent Application No.2007-222395 is hereby incorporated herein by reference.

BACKGROUND

1. Technical Field

The technical field relates to a camera system, and more particularlyrelates to a system used in digital single lens reflex cameras of theinterchangeable lens type.

2. Description of the Related Art

Digital single lens reflex cameras with which an optical image of asubject can be converted into an electrical image signal and outputtedhave rapidly grown in popularity in recent years. With these digitalsingle lens reflex cameras, when the user looks through the viewfinderto view a subject, the light that is incident on the imaging lens (thatis, the subject image) is reflected by a reflecting mirror disposedalong the imaging optical path beyond the lens, and this changes theoptical path to go through a pentaprism or the like and obtains apositive image that is guided to the optical viewfinder, allowing thesubject image that has passed through the lens to be seen through theoptical viewfinder. Therefore, the position where the viewfinder opticalpath is formed is usually the home position of the reflecting mirror.Meanwhile, when a lens is used for imaging, the reflecting mirrorinstantly changes its position, and is retracted from the imagingoptical path, which switches the viewfinder optical path to the imagingoptical path, and instantly returns to its home position as soon asimaging is complete. This method is common to a conventional film cameraand a digital camera.

One of the features of a digital camera is that an image can be capturedwhile the user looks at a display device (such as a liquid crystalmonitor), and the captured image can be checked right after it iscaptured. However, when a conventional single reflex lens reflectingmirror is used, a liquid crystal monitor cannot be used during imagecapture. This means that image capture cannot be performed using aliquid crystal monitor, and the user instead has to look through theviewfinder, and this makes the camera very difficult to use for a novicewho is inexperienced with digital camera photography.

In view of this, a digital single lens reflex camera has been proposedwith which images can be captured while the user looks at a liquidcrystal monitor, for example (see Japanese Laid-Open Patent Application2001-125173, for instance).

Also, in recent years consumers have wanted digital single lens reflexcameras that are not only capable of capturing still pictures, but alsohave functions such as capturing moving pictures.

With the digital single lens reflex camera disclosed in JapaneseLaid-Open Patent Application 2001-125173, however, the capture of movingpictures is not taken into account, so even if an interchangeable lensthat is compatible with moving picture capture is mounted to the camerabody, it may still be impossible to capture moving pictures, which isinconvenient to the user.

SUMMARY

A camera body according to a first aspect is used in a camera systemalong with an interchangeable lens unit having an optical systemconfigured to form an optical image of a subject. This camera bodycomprises an imaging unit, a movable reflecting mirror, and a mirrorcontroller. The imaging unit is configured to convert the optical imageinto an image signal and acquire an image of the subject. The reflectingmirror has a first state of being in the optical path of the opticalsystem and a second state of being outside the optical path. The mirrorcontroller is configured to retract the reflecting mirror to outside theoptical path of the optical system when the reflecting mirror is in thefirst state of being in the optical path of the optical system and amoving picture photography mode is selected, which is a mode forcapturing moving pictures.

A camera body according to a second aspect is a camera body according tothe first aspect, further comprising a display unit configured todisplay a real-time image acquired by the imaging unit in the movingpicture photography mode and in the second state in which the reflectingmirror is retracted out of the optical path of the optical system.

A camera body according to a third aspect is a camera body according tothe second aspect, wherein the recording of a moving picture iscommenced when a moving picture recording start control is operated inthe moving picture photography mode and in the second state in which thereflecting mirror is retracted out of the optical path of the opticalsystem.

A camera system according to a fourth aspect comprises an opticalsystem, an imaging unit, a movable reflecting mirror, and a mirrorcontroller. The optical system is configured to form an optical image ofa subject. The imaging unit is configured to convert the optical imageinto an image signal and acquire an image of the subject. The reflectingmirror has a first state of being in the optical path of the opticalsystem and a second state of being outside the optical path. The mirrorcontroller is configured to retract the reflecting mirror to outside theoptical path of the optical system when the reflecting mirror is in thefirst state of being in the optical path of the optical system and amoving picture photography mode is selected, which is a mode forcapturing moving pictures.

A camera system according to a fifth aspect is a camera system accordingto the fourth aspect, further comprising a display unit configured todisplay a real-time image acquired by the imaging unit in the movingpicture photography mode and in the second state in which the reflectingmirror is retracted out of the optical path of the optical system.

A camera system according to a sixth aspect is a camera system accordingto the fifth aspect, wherein the recording of a moving picture iscommenced when a moving picture recording start control is operated inthe moving picture photography mode and in the second state in which thereflecting mirror is retracted out of the optical path of the opticalsystem.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings which form a part of thisoriginal disclosure:

FIG. 1 is a block diagram of the configuration of a camera system;

FIG. 2 is a block diagram of the configuration of a camera body;

FIG. 3A is a simplified diagram of the configuration of a camera body,and FIG. 3B is a simplified diagram of the configuration of a camerabody;

FIG. 4 is a cross section at the wide angle end of an interchangeablelens unit;

FIG. 5 is a cross section at the telephoto end of an interchangeablelens unit;

FIG. 6 is an exploded oblique view of the configuration of a focus lensunit;

FIG. 7 is an assembled oblique view of the configuration of a focus lensunit;

FIG. 8 is an oblique view of an ultrasonic actuator unit;

FIG. 9 is a simplified diagram of an ultrasonic actuator unit;

FIG. 10 is a diagram illustrating a viewfinder photography mode;

FIG. 11 is a diagram illustrating a monitor photography mode;

FIG. 12 is a flowchart of moving picture imaging determinationprocessing;

FIG. 13 is a flowchart of external monitor detection processing;

FIG. 14 is a diagram illustrating the connection of a camera system andan external monitor via an AV cable;

FIG. 15 is a flowchart of display unit detection processing;

FIG. 16 is a diagram illustrating the monitor photography mode when thedisplay unit is used by opening up the camera body;

FIG. 17 is a simplified oblique view of a camera system; and

FIG. 18 is a flowchart of self-timer determination processing.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Selected embodiments will now be explained with reference to thedrawings. It will be apparent to those skilled in the art from thisdisclosure that the following descriptions of the embodiments areprovided for illustration only and not for the purpose of limiting theinvention as defined by the appended claims and their equivalents.

First Embodiment 1: Overall Configuration of Camera System

The overall configuration of the camera system 1 according to the firstembodiment will now be described through reference to FIGS. 1 to 3. FIG.1 is a block diagram of the camera system 1. FIG. 2 is a block diagramof the camera body 3. FIGS. 3A and 3B are simplified configurationdiagrams of the camera body 3B.

As shown in FIG. 1, the camera system 1 is an interchangeable lens typeof digital single lens reflex camera, and mainly includes a camera body3 having the main functions of the camera system 1, and aninterchangeable lens unit 2 that is removably mounted to the camera body3. The interchangeable lens unit 2 is mounted to a body mount 4 (anexample of a mounting unit) provided to the front face of the camerabody 3 via a lens mount 79.

1.1: Camera Body

As shown in FIGS. 1 and 2, the camera body 3 mainly includes an imagingunit 71 that captures images of a subject, a body microcomputer 10serving as a body controller that controls the various operations of theimaging unit 71 and so forth, an image display unit 72 that displaysvarious information and captured images, an image storage unit 73 thatstores image data, and a viewfinder optical system 22 through which asubject image is viewed.

The imaging unit 71 mainly includes a quick return mirror 23 that guidesincident light to the viewfinder optical system 22 and a focal pointdetection unit 5, an imaging sensor 11 such as a CCD (charge coupleddevice) that performs opto-electric conversion, a shutter unit 33 thatadjusts the exposure state of the imaging sensor 11, a shuttercontroller 31 that controls the drive of the shutter unit 33 on thebasis of a control signal from the body microcomputer 10, an imagingsensor drive controller 12 that controls the operation of the imagingsensor 11, and the focal point detection unit 5 that detects the focalpoint (the focused state of the subject image). The focal pointdetection unit 5 performs focal point detection by a standard phasedifference detection method, for example. Depending on how the camerasystem 1 is used, two different methods can be used for focal pointdetection, namely, a phase difference detection method in which theabove-mentioned focal point detection unit 5 is used, or a contrastdetection method based on the image signal outputted from the imagingsensor 11. In the case of a contrast detection method, a contrast valueis found and the focal point is detected by the body microcomputer 10.Specifically, the body microcomputer 10 can be said to include acontrast detector. This focal point detection result is sent to the lensmicrocomputer 40 (discussed below) and used to drive a focus lens group(second lens group L2).

The imaging sensor 11 is, for example, a CCD (charge coupled device)sensor that converts an optical image formed by an imaging opticalsystem L into an electrical signal. The imaging sensor 11 is driven by atiming signal generated by the imaging sensor drive controller 12. Theimaging sensor 11 may also be a CMOS (complementary metal-oxidesemiconductor) sensor.

The body microcomputer 10 is the main control apparatus for the camerabody 3, and controls various sequences. More specifically, a CPU, ROM,and RAM are installed in the body microcomputer 10, and the CPU readsthe programs loaded in the ROM, which allows the body microcomputer 10to carry out its various functions. For example, the body microcomputer10 has the function of detecting that the interchangeable lens 2 hasbeen mounted to the camera body 3, the function of controlling theoperation of the interchangeable lens unit 2 and acquiring informationthat is essential to controlling the camera system 1, such as focallength information, from the interchangeable lens unit 2, and so forth.The body microcomputer 10 also has the function of determining whetheror not the interchangeable lens unit 2 is compatible with moving picturephotography (determination unit), and the function of setting theoperation of the imaging sensor 11 to either a still picture photographymode or a moving picture photography mode via the imaging sensor drivecontroller 12. As shown in FIG. 1, the body microcomputer 10 isconnected to the various components provided to the camera body 3.

The body microcomputer 10 is also able to receive signals (an example offirst operation information) from a power switch 25 (shown in FIG. 3B),a release button 30, a mode switching dial 26, a cross key 27, a menusetting button 28, a set button 29, a viewfinder switching button 34,and a moving picture photography button 35. The body microcomputer 10 isan example of a determination unit, a detector, and a device detector.

Furthermore, as shown in FIG. 2, various information related to thecamera body 3 (body information) is stored in a memory 38 in the bodymicrocomputer 10. This body information includes, for example, the nameof the manufacturer of the camera body 3, the manufacture date, themodel number, the version of software installed in the bodymicrocomputer 10, information related to firmware updates, and othersuch information related to the model for specifying the camera body 3(camera specification information). Information sent from the lensmicrocomputer 40 can be stored in the memory 38.

The body microcomputer 10 controls the entire camera system, such as theimaging sensor 11, according to the operation of the release button 30and the like. The body microcomputer 10 sends a vertical synchronizationsignal to a timing generator. Parallel with this, the body microcomputer10 produces an exposure synchronization signal on the basis of thevertical synchronization signal. The body microcomputer 10 repeatedlyand periodically sends the exposure synchronization signal thus producedto the lens microcomputer 40 through the body mount 4 and the lens mount79.

The body mount 4 can be mechanically and electrically connected to thelens mount 79 of the interchangeable lens unit 2. The body mount 4 isable to exchange information with the interchangeable lens unit 2 viathe lens mount 79. For example, the body mount 4 sends the exposuresynchronization signal received from the body microcomputer 10 to thelens microcomputer 40 via the lens mount 79. Also, the body mount 4sends other control signals received from the body microcomputer 10 tothe lens microcomputer 40 via the lens mount 79. The body mount 4 alsosends the body microcomputer 10 signals received from the lensmicrocomputer 40 via the lens mount 79. Also, the body mount 4 suppliesthe power supplied from a power supply unit (not shown) to the entireinterchangeable lens unit 2 through the lens mount 79.

As shown in FIGS. 3A and 3B, the case 3 a of the camera body 3 issupported by the user during photography of a subject. The rear face ofthe case 3 a is provided with a display unit 20, the power switch 25,the mode switching dial 26, the cross key 27, the menu setting button28, the set button 29, the viewfinder switching button 34, and themoving picture photography button 35.

The power switch 25 is used to switch on the power to the camera system1 or the camera body 3. When the power is switched on with the powerswitch 25, power is supplied to the various components of the camerabody 3 and the interchangeable lens unit 2. The mode switching dial 26is used to switch between operating modes, such as the still picturephotography mode, the moving picture photography mode, and thereproduction mode. The user can turn the mode switching dial 26 toswitch the operating mode. When the still picture photography mode isselected with the mode switching dial 26, the operating mode is switchedto the still picture photography mode, and when the moving picturephotography mode is selected with the mode switching dial 26, theoperating mode is switched to the moving picture photography mode. Inthe moving picture photography mode, moving picture photography ispossible. Further, when the reproduction mode is selected with the modeswitching dial 26, the operating mode is switched to the reproductionmode, and the captured image can be displayed on the display unit 20.

The menu setting button 28 is used to set the various operations of thecamera system 1. The cross key 27 is a control member with which theuser presses the top, bottom, left, or right part of the key to selectthe desired menu from the various menu screens displayed on the displayunit 20. The set button 29 is used to execute the various menus. Theviewfinder switching button 34 is used to switch photography modesbetween the viewfinder photography mode and the monitor photographymode. The moving picture photography button is used to start or stopmoving picture photography. Whether the operating mode selected on themode switching dial 26 is the moving picture photography mode or thestill picture photography mode, pressing the moving picture photographybutton 35 forcibly sets the moving picture photography mode and startsmoving picture photography, regardless of the setting on the modeswitching dial 26. Furthermore, if the moving picture photography button35 is pressed during moving picture photography, the moving picturephotography is ended and the operating mode switches to the one selectedon the mode switching dial 26, namely, the operating mode prior to thestart of the moving picture photography. For example, if the stillpicture photography mode has been selected with the mode switching dial26 when the moving picture photography button 35 is pressed, theoperating mode automatically changes to the still picture photographymode after the moving picture photography button 35 has been pressedagain.

In this embodiment, the “operating mode” refers to the function of thecamera system 1, such as capturing or reproducing an image. In contrast,“photography mode” indicates the state of the camera system 1 selectedin the capture of an image.

As shown in FIG. 3B, the release button 30 is provided to the top faceof the case 3 a. When the release button 30 is pressed, a timing signalis outputted to the body microcomputer 10. The release button 30 is atwo-position switch that can be pressed halfway or all the way down.When the user presses the release button 30 halfway down, processing forlight metering and ranging begins. Pressing the button halfway down alsosupplies power to the various components, including the bodymicrocomputer 10 and the lens microcomputer 40. When the release button30 is then pressed all the way down, a timing signal is outputted to thebody microcomputer 10. The shutter controller 31 drives a shutter drivemotor 32 and operates the shutter unit 33 according to the controlsignal outputted from the body microcomputer 10 upon receipt of thetiming signal. The shutter drive motor 32 is preferably a motor that isseparate and independent from the motor (not shown) used to flip up thequick return mirror 23 to outside the optical axis AZ, but there is noproblem if one motor performs both tasks.

As shown in FIG. 2, in the still picture photography mode, the bodymicrocomputer 10 that has received a timing signal after operation ofthe release button 30 outputs a control signal to a strobe controller47. The strobe controller 47 turns on a strobe 48, constituted by an LEDor the like, on the basis of the control signal. The strobe 48 iscontrolled according to the amount of light received by the imagingsensor 11. Specifically, the strobe controller 47 automatically turns onthe light in conjunction with shutter operation when the output of theimage signal from the imaging sensor 11 is at or below a specific value.On the other hand, if the image signal output is over the specificvalue, the strobe controller 47 controls the strobe 48 so that no lightis emitted.

A strobe switch 49 is a control member for setting the operation of thestrobe 48 regardless of the output of the above-mentioned imaging sensor11. Specifically, the strobe controller 47 turns on the strobe 48 whenthe strobe switch 49 is “on,” and turns off the strobe 48 when theswitch is “off.”

In the moving picture photography mode, the release button 30 or themoving picture photography button 35 is operated, and the strobe 48(constituted by an LED or the like) functions as a video light, so thatlight is shined toward the subject during moving picture photography.

The image signal (still picture or moving picture) outputted from theimaging sensor 11 is sent to and processed by an analog signal processor13, an A/D converter 14, a digital signal processor 15, a buffer memory16, and an image compressor 17, in that order. The analog signalprocessor 13 subjects the image signal outputted by the imaging sensor11 to analog signal processing, such as gamma processing. The A/Dconverter 14 converts the analog signal outputted from the analog signalprocessor 13 into a digital signal. The digital signal processor 15subjects the image signal converted into a digital signal by the A/Dconverter 14 to digital signal processing, such as noise elimination orcontour enhancement. The buffer memory 16 is a RAM, which temporarilystores image signals.

The image signal stored in the buffer memory 16 is sent to and processedby the image compressor 17 and an image recorder 18, in that order. Theimage signal stored in the buffer memory 16 is read at a command from animage recording controller 19, and sent to the image compressor 17. Datafor the image signal sent to the image compressor 17 is compressed intoan image signal according to a command from the image recordingcontroller 19. The image signal is compressed by this compressionprocessing to a data size that is smaller than that of the originaldata. The compression method can be, for example, JPEG (JointPhotographic Experts Group) in the case of a still picture. In the caseof a moving picture, MPEG (Moving Picture Experts Group) is used. Also,an H.264/AVC format in which a plurality of frames of image signals arecompressed together can be used. The compressed image signal is recordedto the image recorder 18 by the image recording controller 19.

The image recorder 18 is an internal memory or a removable memory, forexample, that records while referencing specific information to berecorded with the image signal on the basis of a command from the imagerecording controller 19. The specific information to be recorded alongwith the image signal includes the date and time the image was captured,focal length information, shutter speed information, aperture valueinformation, and photography mode information. The format for thisinformation includes the Exif (registered trademark) format and formatssimilar to the Exif (registered trademark) format. The moving picturefile may be, for example, an H.264/AVC format or a format similar to anH.264/AVC format.

The display unit 20 is a liquid crystal monitor, for example, anddisplays as a visible image the image signal recorded to the imagerecorder 18 or the buffer memory 16 based on a command from an imagedisplay controller 21. The display modes of the display unit 20 are adisplay mode in which just the image signal is displayed as a visibleimage, and a display mode in which the image signal and information fromthe time of capture are displayed as a visible image. The display unit20 is a variable-angle monitor with which the angle can be freelychanged with respect to the case 3 a of the camera body 3, and the anglecan be tilted upward by means of a hinge mechanism 112. Morespecifically, the display unit 20 can be in a closed state in which itis disposed parallel to the rear face of the case 3 a, or an open statein which it is disposed at a tilt so as to face upward with respect tothe rear face of the case 3 a.

A pin 110 is fixed to the display unit 20 for detecting whether it isopen or closed. To detect the pin 110, an open/closed detection sensor111 (an example of a detector) is provided to the camera body 3. Theopen/closed detection sensor 111 is fixed to the case 3 a of the camerabody 3.

The body microcomputer 10 determines whether the display unit 20 is openor closed on the basis of a detection signal from the open/closeddetection sensor 111 (an example of third control information). Forexample, as shown in FIG. 1, when the display unit 20 is closed, the pin110 is disposed within the detection region of the open/closed detectionsensor 111, so if the pin 110 is detected by the open/closed detectionsensor 111, it can be concluded that the display unit 20 is closed. Asshown in FIG. 16, when the display unit 20 is open (more precisely, whenthe display unit 20 is not closed), the pin 110 is not disposed withinthe detection region of the open/closed detection sensor 111, so if thepin 110 is not detected by the open/closed detection sensor 111, it canbe concluded that the display unit 20 is open, and not closed.

Thus, whether the display unit 20 is open or closed can be determined onthe basis of the detection signal of the open/closed detection sensor111. The direction in which the display unit 20 opens is not limited toup and down as in this embodiment, and may be some other direction.

An AV cable connection detecting circuit 97 (an example of a detector)detects that an AV cable 100 used for AV output terminal connection isconnected to an AV output terminal 98 (an example of an image outputunit). The AV cable connection detecting circuit 97 has, for example, aninput terminal connected to the body microcomputer 10, and a switch thatgrounds this input terminal. In a state in which the power to the camerasystem 1 is on, the voltage of the input terminal is pulled up to aspecific drive voltage. When the pin jack of the AV cable 100 isinserted, for example, into the AV output terminal 98, the groundingswitch changes to a closed state. As a result, the voltage level of theinput terminal is inverted from a high level to a low level. Theconnection of the AV cable 100 can be detected by monitoring the changein the voltage level of the input terminal (an example of second controlinformation). For instance, monitoring of the voltage level of the inputterminal is carried out by the body microcomputer 10. The bodymicrocomputer 10 here can be considered an example of a detector.

When the AV cable 100 is connected to the AV output terminal 98, theNTSC signal produced by a video signal output circuit 99 is outputtedthrough the AV output terminal 98 and the AV cable 100 to an externalmonitor 101 connected to the AV cable 100. This allows a real-time imageor an image that has been recorded to be displayed on the externalmonitor 101.

The AV cable 100 is not limited to being a cable that transmits NTSCsignals, and may be an interface cable that transmits control signals atthe same time, such as a USB (Universal Serial Bus) cable.

The camera system 1 has a self-timer function. More specifically, asshown in FIG. 2, the camera body 3 is provided with a self-timerfunction setting button 95 (an example of a detector) for switching toself-timer photography mode. Information about the operation of theself-timer function setting button 95 (an example of fourth controlinformation) is sent to the body microcomputer 10. In self-timerphotography mode, a still picture is captured after a specific amount oftime has elapsed since the release button 30 of the camera body 3 or aremote control (not shown) was pressed. In the self-timer photographymode, it is possible to set, for example, the time from the issuance ofa photography command until the first image is captured (waiting time),the number of continuous images captured, and the interval between imagecaptures.

As shown in FIG. 1, the quick return mirror 23 is constituted by a mainmirror 23 a capable of reflecting and transmitting incident light, and asub-mirror 23 b that is provided on the rear face side of the mainmirror 23 a and reflects light transmitted by the main mirror 23 a. Thequick return mirror 23 is rotatably supported by the case 3 a, and canbe in a first position disposed in the optical path, or a secondposition that is retracted out of the optical path. A quick returnmirror controller 36 is able to drive the quick return mirror 23 tothese two positions.

In a state in which the quick return mirror 23 is disposed within theoptical path, incident light is split into two beams by the main mirror23 a, and the reflected beam is guided to the viewfinder optical system22. The transmitted beam is reflected by the sub-mirror 23 b andutilized as an AF light beam by the focal point detection unit 5. Duringordinary photography, the quick return mirror 23 is flipped up outsidethe optical axis AZ by the quick return mirror controller 36, theshutter unit 33 is opened, and a subject image is formed on the imagingface of the imaging sensor 11. When photography is not being performed,as shown in FIG. 1, the quick return mirror 23 is disposed along theoptical axis AZ, and the shutter unit 33 is closed.

The viewfinder optical system 22 is constituted by a viewfinder screen 6on which a subject image is formed, a pentaprism 7 that converts thesubject image into an erect image, an eyepiece lens 8 that guides theerect image of the subject to a viewfinder eyepiece window 9, and theviewfinder eyepiece window 9 that is used by the user to view thesubject image.

1.2: Interchangeable Lens Unit

As shown in FIG. 1, the interchangeable lens unit 2 mainly includes animaging optical system L for forming an optical image of a subject onthe imaging sensor 11 in the camera system 1, a focus lens group drivecontroller 41 that performs focusing by driving a second lens group L2(focus lens group) in the optical axis direction, an aperture drivecontroller 42 for adjusting the aperture, and the lens microcomputer 40for controlling the operation of the interchangeable lens unit 2. Thesecond lens group L2 is an example of a focal point adjuster, the focuslens group drive controller 41 is an example of a lens controller, andthe lens microcomputer 40 is an example of a lens controller.

The focus lens group drive controller 41 mainly controls the drive ofthe second lens group L2 (focus lens group; discussed below) thatadjusts the focus. The aperture drive controller 42 mainly controls thedrive of an aperture unit 43 for adjusting how open or closed theaperture is.

The lens microcomputer 40 is the main control apparatus for theinterchangeable lens unit 2, and is connected to the various componentsinstalled in the interchangeable lens unit 2. More specifically, a CPU,ROM, and RAM are installed in the lens microcomputer 40, and the CPUreads the programs loaded in the ROM, which allows the lensmicrocomputer 40 to carry out its various functions. Also, the bodymicrocomputer 10 and the lens microcomputer 40 are connected byelectrical contacts (not shown) provided to the lens mount 79, allowinginformation to be exchanged between the two.

Various information (lens information) related to the interchangeablelens unit 2 is stored in a memory 44 of the lens microcomputer 40. Morespecifically, focal length information indicating the maximum andminimum values for focal length of the interchangeable lens unit 2(focal length variable range), or the object point distance, etc., isstored. The various information stored in the memory 44 is sent to thecamera body 3 side when the interchangeable lens unit 2 is attached tothe camera body 3 so that it can be used during photography. Informationrelated to whether or not the interchangeable lens unit 2 is compatiblewith the above-mentioned moving picture photography is also stored inthe memory 44. The information related to moving picture photographywill be discussed in detail below.

The specific configuration of the interchangeable lens unit 2 will bedescribed through reference to FIGS. 4 to 7. As shown in FIG. 4, an XYZthree-dimensional coordinate system is set up in which the directionalong the optical axis AZ of the interchangeable lens unit 2 serves asthe Z axis direction (the subject side is the positive side, and thecamera body 3 side is the negative side). The imaging optical system L,which has four lens groups, is installed in the interchangeable lensunit 2. More specifically, the interchangeable lens unit 2 has a firstlens group L1, a second lens group L2, a third lens group L3, and afourth lens group L4. The first lens group L1, second lens group L2,third lens group L3, and fourth lens group L4 are able to move along theoptical axis AZ in the Z axis direction. The second lens group L2 is thelens group that moves along the optical axis AZ in the Z axis directionto perform focusing.

The interchangeable lens unit 2 has a lens barrel 45 that supports theimaging optical system L. The lens barrel 45 has a fixed frame 50, afirst linear frame 52, a first rotary frame 53, a first holder 54, asecond rotary frame 55, a first lens support frame 57, a second lenssupport frame 58, a third lens support frame 59, a fourth lens supportframe 60, a second holder 61, a filter mount 62, a zoom ring unit 63, afocus ring unit 66, and a lens mount 79.

The first rotary frame 53 is disposed coaxially on the outer peripheralside of the first linear frame 52, and is supported by the first linearframe 52 so as to be capable of rotating around the optical axis AZ.

The first holder 54 is disposed coaxially on the outer peripheral sideof the first rotary frame 53, and its rotation around the optical axisAZ is limited by the first linear frame 52. When the first rotary frame53 rotates around the optical axis AZ, the first holder 54 moves in theZ axis direction without rotating with respect to the first linear frame52 (while rotating with respect to the first rotary frame 53). Three campins 54 a disposed at a constant pitch in the circumferential directionare provided to the portion of the first holder 54 on the negative sidein the Z axis direction.

The second holder 61 is disposed coaxially on the inner peripheral sideof the first linear frame 52, and its rotation around the optical axisAZ is limited by the first linear frame 52. The second holder 61 hasthree cam pins 61 a disposed at a constant pitch in the circumferentialdirection. The cam pins 61 a are inserted into through-linear grooves 52c of the first linear frame 52 and cam though-grooves 53 b of the firstrotary frame 53. Therefore, when the first rotary frame 53 rotatesaround the optical axis AZ, the second holder 61 moves in the Z axisdirection without rotating with respect to the first linear frame 52(while rotating with respect to the first rotary frame 53).

The first linear frame 52 is disposed coaxially on the outer peripheralside of the fixed frame 50, and is supported by the fixed frame 50, thesecond rotary frame 55, and the third lens support frame 59. Therotation of the first linear frame 52 around the optical axis AZ islimited by the fixed frame 50. When the first rotary frame 53 rotatesaround the optical axis AZ, the first linear frame 52 moves in the Zaxis direction without rotating with respect to the fixed frame 50.

The second rotary frame 55 is disposed coaxially on the inner peripheralside of the fixed frame 50, and is supported by the fixed frame 50. Whenthe first rotary frame 53 rotates around the optical axis AZ, the secondrotary frame 55 moves along the optical axis AZ while rotating aroundthe optical axis AZ with respect to the fixed frame 50.

The third lens support frame 59 is disposed coaxially on the innerperipheral side of the second rotary frame 55, and its rotation aroundthe optical axis AZ is limited by the fixed frame 50. When the firstrotary frame 53 rotates around the optical axis AZ, the third lenssupport frame 59 moves in the Z axis direction without rotating withrespect to the fixed frame 50.

The fourth lens support frame 60 is disposed coaxially on the innerperipheral side of the second rotary frame 55, and its rotation aroundthe optical axis AZ is limited by the third lens support frame 59. Whenthe first rotary frame 53 rotates around the optical axis AZ, the fourthlens support frame 60 moves along the optical axis AZ without rotatingwith respect to the third lens support frame 59.

The first lens support frame 57 is fixed to the end of the first holder54, and supports the first lens group L1. The second lens support frame58 supports the second lens group L2. An ultrasonic actuator unit 80(discussed below) and an anti-rotation part (not shown) disposed at asubstantially opposite position on the circumference thereof areprovided to the second lens support frame 58.

The third lens support frame 59 supports the third lens group L3 and hasthree cam pins 59 a disposed at a constant pitch in the circumferentialdirection.

The fourth lens support frame 60 supports the fourth lens group L4 andhas three cam pins 60 a disposed at a constant pitch in thecircumferential direction.

The first rotary frame 53 is a cam ring that is cylindrical in shape,and has three cam though-grooves 53 a and three cam though-grooves 53 bthat are tilted with respect to the optical axis AZ. The cam pins 54 aof the first holder 54 are inserted into the cam though-grooves 53 a.The cam pins 61 a of the second holder 61 are inserted into the camthough-grooves 53 b. Three slots 53 c into which the cam pins 55 a ofthe second rotary frame 55 are inserted are provided to the end of thefirst rotary frame 53. The cam pins 55 a include one long pin and twoshort pins, and only the long pin is inserted into the slots 53 c.

The first linear frame 52 is a cam ring that is cylindrical in shape,and has three cam though-grooves 52 b into which the cam pins 54 a ofthe first holder 54 are inserted. Three linear through-grooves 52 c intowhich the cam pins 61 a of the second holder 61 are inserted are formedat positions where they will not interfere with the cam though-grooves52 b. Through-holes 52 d into which the cam pins 59 a provided to thethird lens support frame 59 are inserted are provided to the end of thefirst linear frame 52 to allow integral movement with the third lenssupport frame 59 in the Z axis direction.

Three linear through-grooves 50 a for moving the first linear frame 52in the Z axis direction are formed in the fixed frame 50. Three camthough-grooves 50 b that are tilted with respect to the Z axis directionare formed at a constant pitch in the circumferential direction, at aportion where there is no interference with the linear through-grooves50 a, in order to move the second rotary frame 55 in a direction alongthe optical axis AZ.

Three cam through-grooves 55 c that are tilted with respect to the Zaxis direction and engage with the cam pins 59 a of the third lenssupport frame 59 are formed at a constant pitch in the circumferentialdirection on the outer peripheral face of the second rotary frame 55.Three cam through-grooves 55 d that are tilted with respect to the Zaxis direction and engage with the cam pins 60 a of the fourth lenssupport frame 60 are formed at a constant pitch in the circumferentialdirection.

The filter mount 62 is cylindrical in shape, and a polarizing filter,protective filter, or other such optical filter and female threads forattaching a conversion lens are formed on the Z axis direction positiveside (subject side). The filter mount 62 is fixed to the first holder 54by three attachment screws, etc.

The zoom ring unit 63 has a zoom ring 64 and a first angle detector 65(FIG. 1) that detects the rotational angle of the zoom ring 64. The zoomring 64 is cylindrical in shape, and is supported rotatably around theoptical axis AZ, while restricted in the direction along the opticalaxis AZ with respect to a ring base 69 fixed to the fixed frame 50. Aconcave part (not shown) that is restricted only around the optical axisAZ and is not restricted in the direction along the optical axis AZ isformed on the inner peripheral part of the zoom ring 64. This concavepart engages with a convex component (not shown) provided to the outerperipheral part of the first rotary frame 53. Thus, the zoom ring 64rotates integrally with the first holder 54. Also, the first angledetector 65 detects the rotational angle and rotation direction of thezoom ring 64, and transmits focal length information to the lensmicrocomputer 40. The focal length of the imaging optical system L isdisplayed on the outer peripheral face of the zoom ring 64. The absolutepositions of the lens groups L1 to L4 can be detected by a detectingsensor (not shown) that is linked to the rotational angle of the zoomring 64.

The focus ring unit 66 has a focus ring 67 and a second angle detector68 (FIG. 1) that detects the rotational angle of the focus ring 67. Thefocus ring 67 is cylindrical in shape, and is supported rotatably aroundthe optical axis AZ, while restricted in the direction along the opticalaxis AZ with respect to a ring base 69 fixed to the fixed frame 50.Also, the rotational angle and rotation direction of the focus ring 67can be detected by the second angle detector 68. This second angledetector 68 detects, for example, whether or not protrusions formed atregular intervals in the Z axis direction all the way around the focusring 67 have passed between the light emitting part and the lightreceiving part that are the constituent portions of two photosensors(not shown), and thereby detects the rotational angle and rotationdirection of the focus ring 67. The second angle detector 68 detects therotational angle and rotation direction of the focus ring 67 set by theuser, and transmits object point distance information to the lensmicrocomputer 40.

The lens mount 79 has a lens mount contact (not shown), and signals aretransmitted back and forth between the lens microcomputer 40 and thebody microcomputer 10 via a lens mount contact (not shown) of the bodymount 4. Also, the lens mount 79 is fixed to the fixed frame 50 via themount base 70.

As shown in FIGS. 6 and 7, a focus lens unit 78 that can move in adirection along the optical axis AZ as the focusing proceeds has thesecond lens group L2, the second lens support frame 58, the secondholder 61, guide poles 74 a and 74 b, a two-group fixing frame 75, theultrasonic actuator unit 80, a magnetic scale 76, and a magnetic sensor77. The second lens support frame 58 supports the second lens group L2(focus lens group). The ends of the guide pole 74 a are included in theultrasonic actuator unit 80 and fixed to the two-group fixing frame 75and the second holder 61. The guide pole 74 b extends in the Z axisdirection from a fixing portion 58 b of the second lens support frame58, and is inserted into a hole 75 a in the two-group fixing frame 75.The second lens support frame 58 is supported movably in the Z axisdirection by the two-group fixing frame 75. The second lens supportframe 58 is driven in the Z axis direction by the ultrasonic actuatorunit 80.

The ultrasonic actuator unit 80 has a movable part 80 a and a fixed part80 b. The movable part 80 a is fixed with screws or the like to thefixing portion 58 b of the second lens support frame 58. When a specificcurrent is sent to the ultrasonic actuator unit 80, the movable part 80a moves in the Z axis direction with respect to the fixed part 80 b, andthe second lens support frame 58 is driven in the Z axis direction as aresult.

The magnetic scale 76 and magnetic sensor 77 constitute a positiondetecting unit that detects the position of the second lens supportframe 58 with respect to the two-group fixing frame 75. The magneticscale 76 is fixed to the second lens support frame 58 and is magnetizedat regular intervals in the Z axis direction. The magnetic sensor 77 isan MR sensor or the like that detects signals from the magnetic scale76, and is fixed to the two-group fixing frame 75. A specific spacing ismaintained between the magnetic sensor 77 and the magnetic scale 76.Performing position detection and feedback control with the magneticsensor 77 affords a linear actuator that has high-speed response as wellas high resolution, high accuracy, quiet operation, and high torque.Consequently, focus characteristics that are ideal for moving picturephotography can be obtained. Furthermore, the home position of thesecond lens group L2, that is, the second lens support frame 58, can bedetected with a photosensor or the like (not shown). Thus detecting thehome position makes it possible to detect the absolute position of thesecond lens group L2 with respect to the lens mount 79. Also, as to therelative position from the home position, if the output value from themagnetic sensor 77 is counted, where the second lens group L2 is locatedcan always be detected. In other words, it is always possible to detectthe current position of the second lens group L2, using the lens mount79 as a reference, by detecting the relative position away from the homeposition.

Next, the ultrasonic actuator unit 80 will be described throughreference to FIGS. 8 and 9. FIG. 8 is an oblique view of the ultrasonicactuator unit. FIG. 9 is a cross section of the ultrasonic actuatorunit.

As shown in FIGS. 8 and 9, in the ultrasonic actuator unit 80,substantially spherical drivers 82 are provided at two places on thesurface of a piezoelectric element 81 composed of PZT, quartz crystal,or another such piezoelectric material. These two places correspond tothe approximate center of the antinode of flexural vibration of thepiezoelectric element 81, and the vibration of the piezoelectric element81 can be more effectively utilized by providing the drivers 82 at theselocations.

Examples of the material of the drivers 82 include zirconia, alumina,silicon nitride, silicon carbide, and tungsten carbide. The shape of thedrivers 82 is substantially spherical, and using a substantiallyspherical shape reduces the contact surface area of the piezoelectricelement 81 in the lengthwise direction. Consequently, there is lessimpairment of the flexural vibration of the piezoelectric element 81,and as a result its efficiency as an ultrasonic actuator can beimproved.

A power supply electrode 88 that is divided in four is provided to thefront face of the piezoelectric element 81, and these power supplyelectrodes 88 are connected to wires 89 by solder 86. The wires 89 areguided to the outside through holes (not shown) provided to an innercase 84. When voltage is supplied through these wires 89 to the powersupply electrodes 88 of the piezoelectric element 81, the piezoelectricelement 81 vibrates according to the frequency of the voltage. Theportion of the piezoelectric element 81 where the solder 86 is formed isthe node periphery of stretching vibration and flexural vibration. Ifthis node is used as the site where the wires 89 are connected, thiswill reduce the adverse effect on the vibration of the piezoelectricelement 81, that is, the unnecessary load on the piezoelectric element81 caused by forming the solder 86.

The ultrasonic actuator unit 80 mainly has the movable part 80 a and thefixed part 80 b. The movable part 80 a has the piezoelectric element 81,the drivers 82, the inner case 84, an outer case 90, guide balls 91, aretainer 92, and an outer case cover 93. The fixed part 80 b has amoving body 83, a diaphragm 94, and the guide pole 74 a.

The drivers 82 support the moving body 83, and the drivers 82 undergosubstantially elliptical motion under the vibration of the piezoelectricelement 81, which causes the drivers 82 to move reciprocally in the Zaxis direction with respect to the moving body 83. Specifically, thestretching vibration direction of the piezoelectric element 81 is thesame as the direction in which the moving body 83 is able to move. Also,the flexural vibration direction is perpendicular to the movabledirection with respect to the moving body 83, and is a direction thatlinks the piezoelectric element 81 and the moving body 83 (that is, thedirection in which the drivers 82 support the moving body 83).

Alumina is an example of the material of the moving body 83. If aluminais used for the drivers 82, then from the standpoint of wear, thealumina of the moving body 83 is preferably softer than the alumina ofthe drivers 82.

The piezoelectric element 81 is housed in the inner case 84, and thepiezoelectric element 81 is supported by a support 85 provided insidethe inner case 84. The support 85 is made from electroconductivesilicone rubber, for example. Specifically, the piezoelectric element 81is disposed in the inner case 84 so that the stretching direction of thepiezoelectric element 81 is the same as the direction in which themoving body 83 is able to move (the Z axis direction, a direction alongthe optical axis AZ). Side wall supports 85 a and 85 c are provided tothe inner side walls of the inner case 84 in the same direction as thedirection in which the moving body 83 is able to move, and side pressureis exerted on the inner side walls. A rear face support 85 b is providedto the inner bottom face of the inner case 84, which supports thepiezoelectric element 81 and thereby exerts a pressing force. The rearface support 85 b is provided so that the two drivers 82 here supportthe moving body 83 at substantially the same pressure, and this allowsthe moving body 83 to be operated stably.

The inner case 84 is fixed inside the outer case 90. The guide pole 74a, which is cylindrical in shape, is disposed at the upper part of themoving body 83. The guide balls 91 supported by the retainer 92 areprovided at two places above the guide pole 74 a. The outer case cover93 is provided at the upper part of the guide balls 91. The guide balls91 are sandwiched between the outer case cover 93 and the guide pole 74a. Accordingly, a pressing force is exerted on the guide pole 74 a viathe guide balls 91. Consequently, the guide pole 74 a and the movingbody 83 are pressed together and fixed at a specific pressure.

Bearings 90 a and 90 b that support the guide pole 74 a are provided tothe ends of the outer case 90, and the outer case 90 is able to move inthe Z axis direction with respect to the guide pole 74 a. That is, whenthe drivers 82 move elliptically, this allows the movable part 80 a tomove reciprocally in a direction along the optical axis AZ with respectto the fixed part 80 b including the guide pole 74 a and the moving body83.

The operation of the ultrasonic actuator unit 80 constituted as abovewill now be described. When AC voltage of a specific frequency isapplied to a specific power electrode of the piezoelectric element 81, asecondary mode of flexural vibration and a primary mode of stretchingvibration are induced in the piezoelectric element 81. The resonancefrequency of the flexural vibration and the resonance frequency of thestretching vibration are determined by the material, shape, and so forthof the piezoelectric element, and if these two frequencies aresubstantially matched, and voltage with a frequency that is close tothese is applied, a flexural secondary mode and a stretching primarymode will be harmonically induced in the piezoelectric element 81. As aresult, the drivers 82 provided to the piezoelectric element 81 undergoelliptical motion as viewed in the direction of the drawing plane.Specifically, the combination of the flexural vibration and stretchingvibration of the piezoelectric element 81 brings about elliptical motionin the drivers 82. Because of this elliptical motion, the movable part80 a constituted by the drivers 82, etc., can move reciprocally in the Zaxis direction with respect to the moving body 83, and moves integrallywith the second lens group L2.

Thus slidably supporting the focus lens group with the two guide polesdiffers from drive by a conventional rotary cam mechanism in that thereis no backlash or hysteresis, and wobbling (minute reciprocalvibrations) is possible in a direction along the optical axis AZ, so thefocus lens group drive can be controlled so that a focused state isalways maintained, by contrast detection using the imaging sensor 11.This means that moving picture photography is possible even with adigital single lens reflex camera.

1.3: Lens Information Related to Interchangeable Lens Unit

Information related to the interchangeable lens unit 2 will now bedescribed. Various kinds of information related to the interchangeablelens unit 2 (lens information) is stored in the memory 44 of the lensmicrocomputer 40. More specifically, focal length information indicatingthe maximum and minimum values for focal length of the interchangeablelens unit 2 (focal length variable range), or the object point distance,etc., is stored in the memory 44.

The memory 44 also holds information related to whether or not theinterchangeable lens unit 2 is compatible with the above-mentionedmoving picture photography. This information is recorded to a specificaddress in the memory 44 (such as an extra address that is not normallyused).

One possible criterion for determining whether or not theinterchangeable lens unit 2 is compatible with moving picturephotography is whether or not the second lens group L2 (a focus lensgroup) is capable of wobbling (such as minute reciprocal vibration basedon a triangular wave, a sine wave, or another such input signal). If theconstitution is such that the second lens group L2 is supported by guidepoles and the second lens group L2 is driven directly by an ultrasonicactuator or the like, it can be determined that wobbling is possible.Therefore, information related to how the second lens group L2 is drivenmay be used as information related to whether or not the interchangeablelens unit 2 is compatible with moving picture photography.

Furthermore, a constitution in which the amount of magnification changein the image on the imaging sensor 11 is at or below a specific valuewhen the second lens group L2 is wobbled by a specific amount can be thecriterion for determining whether or not there is compatibility withmoving picture photography. Accordingly, information such as this may beused as information related to whether or not the interchangeable lensunit 2 is compatible with moving picture photography.

Compatibility with moving picture photography can sometimes bedetermined from the fact that the interchangeable lens unit 2 iscompatible with a contrast detection method. Therefore, information asto whether or not there is compatibility with a contrast detectionmethod may be used as information related to whether or not theinterchangeable lens unit 2 is compatible with moving picturephotography.

If information such as the above is stored in the interchangeable lensunit 2, then when it is attached to the camera body 3, the determinationunit of the body microcomputer 10 can determine whether or not movingpicture photography is possible on the basis of this information.

Lens information also includes information such as minimum resolution,focusing speed, and so forth that are aspects of the performance of theultrasonic actuator or other actuator used to drive the focus lensgroup. The body microcomputer 10 sets the optimum focusing performanceaccording to the combination with the camera body 3. For instance, theframe rate during moving picture photography (30 fps, 60 fps, etc.), therecording pixel count, and so forth are automatically set for the camerasystem 1 according to this focusing performance. Thus, in combining witha interchangeable lens unit 2 equipped with an ultrasonic actuator, itis even better if the frame rate during moving picture photography canbe automatically set to the optimal frame rate that the camera body 3can attain (60 fps in the case of this embodiment).

When the interchangeable lens unit 2 is attached to the camera body 3,lens information is sent from the lens microcomputer 40 to the bodymicrocomputer 10. This allows the body microcomputer 10 to ascertainvarious information about the interchangeable lens unit 2.

2: Operation of Camera System

The photography operation of the camera system 1 constituted as abovewill now be described.

FIGS. 10 and 11 are concept diagrams during photography with the camerasystem 1. FIG. 10 is a diagram illustrating a viewfinder photographymode, and FIG. 11 is a diagram illustrating a monitor photography mode.

2.1: State Prior to Imaging

As shown in FIGS. 10 and 11, light from the subject (not shown) passesthrough the interchangeable lens unit 2 and is incident on the mainmirror 23 a, which is a semi-transmitting mirror. Part of the lightincident on the case 3 a is reflected and incident on the viewfinderscreen 6, and the rest of the light is transmitted and incident on thesub-mirror 23 b. Light incident on the viewfinder screen 6 forms asubject image. This subject image is converted into an erect image bythe pentaprism 7 and incident on an eyepiece lens 8. Consequently, theuser can view an erect image of the subject through the viewfindereyepiece window 9. Light that is incident on the sub-mirror 23 b isreflected and incident on the focal point detection unit 5.

2.2: Viewfinder Photography Mode and Monitor Photography Mode

This camera system 1 has two photography modes, namely, a viewfinderphotography mode and a monitor photography mode. The viewfinderphotography mode is a mode in which the user captures a still picturewhile looking at the subject through the viewfinder eyepiece window 9.This is the normal photography mode in a conventional single lens reflexcamera. The monitor photography mode is a mode in which the usercaptures a still or moving picture while looking at the subjectdisplayed on the display unit 20, which is a liquid crystal monitor orthe like.

In the viewfinder photography mode, as shown in FIG. 10, the quickreturn mirror 23 is disposed at a specific location along the opticalpath (more precisely, along the optical axis AZ). The subject light isguided to the viewfinder optical system 22, so the user can view thesubject image through the viewfinder eyepiece window 9. When a stillpicture is to be captured, the quick return mirror 23 is flipped upoutside of the optical path, and the shutter unit 33 is opened. As aresult, a subject image is formed on the image face of the imagingsensor 11.

Meanwhile, in the monitor photography mode, as shown in FIG. 11, thequick return mirror 23 is retracted out of the optical path. Thus, animage of the subject, what is called a through image, is displayed onthe display unit 20 via the imaging sensor 11.

2.3: Operation in Viewfinder Photography Mode

The photography operation of the camera system 1 will be described. Thedrive sequence in viewfinder photography mode in which the user looksthrough the viewfinder eyepiece window 9 to capture a still picture willbe described through reference to FIGS. 1 to 4.

When an image is to be captured in viewfinder photography mode, the userpresses the viewfinder switching button 34 provided to the rear face ofthe case 3 a to select the viewfinder photography mode as thephotography mode.

When the user presses the release button 30 half way down, power issupplied to the body microcomputer 10 and the various units in thecamera system 1. The body microcomputer 10 in the camera system 1 thathas actuated by the supply of power receives various lens informationfrom the lens microcomputer 40 in the interchangeable lens unit 2, whichis similarly actuated by the supply of power, through the lens mount 79and the body mount 4, and this information is stored in the built-inmemory 38. Next, the body microcomputer 10 acquires the amount ofdefocus (hereinafter referred to as the Df amount) from the focal pointdetection unit 5, and sends a command to the lens microcomputer 40 todrive the second lens group L2 by this Df amount. The lens microcomputer40 controls the focus lens group drive controller 41 and operates thesecond lens group L2 by the Df amount. While focal point detection anddrive of the second lens group L2 are thus repeated, the Df amountdecreases, and when it reaches a specific amount or less, the bodymicrocomputer 10 that the image is in focus, and drive of the secondlens group L2 is stopped.

After this, when the user presses the body microcomputer 10 all the waydown, the body microcomputer 10 instructs the lens microcomputer 40 toset the aperture value to the one calculated on the basis of the outputfrom a photometer sensor (not shown). The lens microcomputer 40 thencontrols the aperture drive controller 42 and stops down the aperture tothe indicated aperture value. Simultaneously with this aperture valuecommand, the body microcomputer 10 retracts the quick return mirror 23to outside the optical path with the quick return mirror controller 36.Once the quick return mirror 23 has been completely retracted, theimaging sensor drive controller 12 directs the image sensor 11 to bedriven, and directs the shutter unit 33 to be operated. The imagingsensor drive controller 12 also exposes the image sensor 11 for the timeof the shutter speed calculated on the basis of the output from a lightmetering sensor (not shown).

Upon completion of the exposure, the image data read by the imagingsensor drive controller 12 from the image sensor 11 is subjected tospecific image processing, after which it is displayed as a capturedimage on the display unit 20. The image data that has been read from theimage sensor 11 and subjected to the specific image processing iswritten via the image recorder 18 as image data to a storage medium.Also, upon the completion of exposure, the quick return mirror 23 andthe shutter unit 33 are reset to their initial positions. The bodymicrocomputer 10 directs the lens microcomputer 40 to reset the apertureto its open position, and the lens microcomputer 40 issues a resetcommand to the various units. Upon completion of the resetting, the lensmicrocomputer 40 conveys the resetting completion to the bodymicrocomputer 10. The body microcomputer 10 awaits the series ofprocessing after exposure and the completion of resetting from the lensmicrocomputer 40, after which it is confirmed that the release button 30has not been pressed, and the imaging sequence is ended.

2.4: Operation in Monitor Photography Mode

The drive sequence in monitor photography mode, which the user uses thedisplay unit 20 to capture an image, will now be described throughreference to FIGS. 1 to 3B and FIG. 5.

When the display unit 20 is used for imaging, the user operates theviewfinder switching button 34 to select the monitor photography mode.When the monitor photography mode is set, the body microcomputer 10retracts the quick return mirror 23 to outside the optical path.Consequently, light from the subject reaches the imaging sensor 11. Theimaging sensor 11 converts light from the subject that has been imagedon the imaging sensor 11 into image data, and the image data thusacquired can be outputted. The image data read from the imaging sensor11 by the imaging sensor drive controller 12 undergoes specific imageprocessing, after which it is displayed as a captured image on thedisplay unit 20. Thus displaying the captured image on the display unit20 allows the user to monitor the subject without having to look throughthe viewfinder eyepiece window 9.

In this monitor photography mode, contrast-type autofocusing, which isbased on image data produced by the imaging sensor 11, is used as thefocusing method instead of a phase difference detection method in whichthe focal point detection unit 5 is used. When a contrast method is usedas the method for autofocusing in the monitor photography mode with thedisplay unit 20, precise focusing can be achieved with the camerasystem. In this monitor photography mode, contrast autofocusing in whichimage data is used is easier than a conventional phase differencedetection method since image data is produced by the imaging sensor 11in a steady state.

The autofocusing operation by contrast method will now be described.

When performing autofocusing by contrast method, the body microcomputer10 requests contrast AF-use lens information of the lens microcomputer40. This contrast AF-use lens information is data that is necessary inautofocusing by contrast method, and includes, for example, the focusdrive speed, the amount of focal shift, the zoom ratio, and whether ornot contrast autofocus is possible.

The body microcomputer 10 periodically produces a verticalsynchronization signal. The body microcomputer 10 produces an exposuresynchronization signal in parallel with this on the basis of thevertical synchronization signal. This allows an exposure synchronizationsignal to be produced because the body microcomputer 10 ascertains aheadof time the exposure start and end timing, using the verticalsynchronization signal as a reference. The body microcomputer 10 outputsthe vertical synchronization signal to a timing generator (not shown),and outputs the exposure synchronization signal to the lensmicrocomputer 40. The lens microcomputer 40 synchronizes with theexposure synchronization signal and acquires position information aboutthe second lens group L2.

The imaging sensor drive controller 12 periodically produces anelectronic shutter drive signal and the read signal of the imagingsensor 11 on the basis of the vertical synchronization signal. Theimaging sensor drive controller 12 drives the imaging sensor 11 on thebasis of the electronic shutter drive signal and the read signal.Specifically, the imaging sensor 11 reads to a vertical transmitter (notshown) the image data produced by numerous opto-electrical conversionelements (not shown) present in the imaging sensor 11, according to theread signal.

In still picture photography mode, the user presses the release button30 half-way down, and the body microcomputer 10 of the camera system 1receives various kinds of lens information from the lens microcomputer40 in the interchangeable lens unit 2 via the lens mount 79 and the bodymount 4, and this information is stored in the built-in memory 38. Also,the body microcomputer 10 sends an autofocus start command to the lensmicrocomputer 40. When the release button 30 is pressed down half-way,the autofocus start command is a command to start the autofocusingoperation by contrast method. On the basis of this command, the lensmicrocomputer 40 controls the drive of the second lens group L2 in thedirection along the optical axis AZ.

The body microcomputer 10 calculates an evaluation value for use inautofocusing (hereinafter referred to as the AF evaluation value) on thebasis of the received image data. More specifically, there is a knownmethod in which a brightness signal is found from the image dataproduced by the imaging sensor 11, the high-frequency component of thebrightness signal on the screen is added up, and the AF evaluation valueis found. The calculated AF evaluation value is stored in a DRAM (notshown) in a state of being associated with the exposure synchronizationsignal. The lens position information acquired from the lensmicrocomputer 40 is also associated with the exposure synchronizationsignal. Accordingly, the body microcomputer 10 can stored the AFevaluation value in association with lens position information.

Next, the body microcomputer 10 finds the contrast peak on the basis ofthe AF evaluation value stored in the DRAM, and monitors whether or notthe focal point has been selected. More specifically, the position ofthe second lens group L2 at which the AF evaluation value is at itsmaximum value is selected as the focal point. This lens drive method iscommonly known as the mountain climbing method.

In this state, the camera system 1 displays the image data produced bythe imaging sensor 11 as a through-image (what is known as a live viewimage) on the display unit 20. Since this through-image is displayed onthe display unit 20, the user can determine the composition forcapturing a still picture while looking at the display unit 20.

After this, when the user presses the release button 30 all the waydown, the body microcomputer 10 directs that the aperture value be setto the one calculated on the basis of the output from the light meteringsensor (not shown). The lens microcomputer 40 then controls the aperturedrive controller 42 and stops down the aperture until the indicatedaperture value is reached. The imaging sensor drive controller 12directs that the imaging sensor 11 be driven, and directs that theshutter unit 33 be operated. The imaging sensor drive controller 12 alsoexposes the imaging sensor 11 for the length of time of the specificshutter speed calculated from the output of the imaging sensor 11.

Upon completion of the exposure, the image data read from the imagingsensor 11 by the imaging sensor drive controller 12 is subjected tospecific image processing, after which it is displayed as a capturedimaged on the display unit 20. Also, the image data read from theimaging sensor 11 and subjected to the specific image processing iswritten via the image recorder 18 as image data to a storage medium.Also, upon completion of exposure, the quick return mirror 23 ispositioned in a state of being retracted out of the optical path, so theuser can use the monitor photography mode to view the subject as acaptured image on the display unit 20.

When the monitor photography mode is to be exited, the user presses theviewfinder switching button 34, and the system changes to the viewfinderphotography mode in which the subject is viewed through the viewfindereyepiece window 9. When the mode changes to viewfinder photography mode,the quick return mirror 23 is returned to its specific position in theoptical path. The quick return mirror 23 is also returned to itsspecific position in the optical path when the power to the camerasystem 1 is switched off.

2.5: Operation in Moving Picture Photography Mode

The moving picture photography mode is an operating mode for performingmoving picture photography. In moving picture photography, an opticalimage is formed on the imaging sensor 11, and image data is continuouslyproduced by the imaging sensor 11, so in moving picture photography modethe quick return mirror 23 has to be retracted out of the optical path.Accordingly, the moving picture photography mode can be considered as atype of monitor photography mode.

When the camera system 1 is in the viewfinder photography mode when theoperating mode has been switched to moving picture photography mode, thecamera system 1 automatically changes to monitor photography mode sothat the user can view the subject on the display unit 20. Morespecifically, when the quick return mirror 23 is disposed in the opticalpath after the moving picture photography mode has been selected withthe mode switching dial 26, the quick return mirror controller 36retracts the quick return mirror 23 out of the optical path on the basisof a command from the body microcomputer 10, and the camera system 1automatically changes to the monitor photography mode.

In this state, the image data produced by the imaging sensor 11 isdisplayed as a through-image on the display unit 20. Since thisthrough-image is displayed in real time on the display unit 20, the usercan determine the composition for capturing a moving picture whilelooking at the display unit 20, and can clock the timing of the start ofmoving picture recording. In moving picture photography mode, when theuser presses the release button 30 all the way down, moving picturerecording is started with this camera system 1.

Also, when the moving picture photography button 35 is pressed, theoperating mode automatically changes to the moving picture photographymode, and the recording of a moving picture is commenced. Morespecifically, if the quick return mirror 23 is disposed in the opticalpath of the imaging optical system L when the moving picture photographybutton 35 is pressed, the quick return mirror controller 36 retracts thequick return mirror 23 out of the optical path on the basis of a commandfrom the body microcomputer 10. After the quick return mirror 23 isretracted, the recording of a moving picture is automatically commenced.

Once moving picture recording starts, the image data produced by theimaging sensor 11 is outputted at a specific frame rate, and therecording of moving picture data to an image recorder is commenced.While the moving picture is being recorded, autofocusing by theabove-mentioned contrast method is carried out periodically, so thefocal state is kept at a specific level during moving picture recording.

2.6: Determining Moving Picture Photography Compatibility

To perform moving picture photography, the camera body 3 determineswhether or not the interchangeable lens unit 2 has a moving picturephotography function. More specifically, with this camera system 1, ifthe interchangeable lens unit 2 is compatible with moving picturephotography, the operating mode automatically changes to moving picturephotography mode when the interchangeable lens unit 2 is attached to thecamera body 3. The operation of the camera system 1 (moving picturephotography determination processing) in determining whether or notmoving picture photography is possible will now be described throughreference to FIG. 12. FIG. 12 is a flowchart of moving picturephotography determination processing.

As shown in FIG. 12, the body microcomputer 10 of the camera body 3determines whether or not the interchangeable lens unit 2 has beenattached (S11). If it is determined that the interchangeable lens unit 2has been attached, the body microcomputer 10 acquires the lensinformation stored in the memory 44 of the interchangeable lens unit 2(S12). The body microcomputer 10 determines on the basis of the acquiredlens information whether or not the interchangeable lens unit 2 iscompatible with moving picture photography (S13).

This lens information includes information related to whether or not thelens is compatible with moving picture photography as discussed above.For example, this information is recorded to a specific address in thememory 44 of the lens microcomputer 40. More specifically, if theinterchangeable lens unit 2 is compatible with moving picturephotography, information indicating that it is compatible with movingpicture photography is recorded to a specific address. On the otherhand, if the interchangeable lens unit 2 is not compatible with movingpicture photography, no information to that effect is recorded to anyspecific address. Therefore, in a state in which the specific address isnot being used, it is determined that the interchangeable lens unit 2 isnot compatible with moving picture photography.

If the mounted interchangeable lens unit 2 is compatible with movingpicture photography, the moving picture photography function isactivated by the body microcomputer 10 (S14). More specifically, whenthe moving picture photography mode is selected with the mode switchingdial 26, the body microcomputer 10 enables moving picture photographyand does not restrict the setting of the operating mode to the movingpicture photography mode. In other words, the body microcomputer 10 cancontrol the operation of the various components on the basis of controlinformation related to moving picture photography. For instance, themoving picture photography can be started and stopped by pressing therelease button 30 all the way down.

If the interchangeable lens unit 2 is compatible with moving picturephotography, the quick return mirror 23 is automatically retracted outof the optical path (S15). More specifically, the body microcomputer 10sends the quick return mirror controller 36 a signal to retract thequick return mirror 23. On the basis of this retraction signal, thequick return mirror 23 is flipped up and out of the optical path by thequick return mirror controller 36. As a result, light that has passedthrough the imaging optical system L is incident on the imaging sensor11, and a real-time image of the subject is displayed on the displayunit 20.

In this embodiment, the moving picture photography can be started andstopped by pressing the moving picture photography button 35, ratherthan the release button 30. In this case, even if the still picturephotography mode or the reproduction mode has been selected, theoperating mode changes forcibly to moving picture photography mode andthe moving picture photography can be started by pressing the movingpicture photography button 35. This allows moving picture photography tobe started instantly when a situation calls for instant reaction, andthe convenience of moving picture photography can still be enhanced.Also, when the interchangeable lens unit 2 is attached to the camerabody 3, the message to the effect that the moving picture photography ispossible may be displayed on the display unit 20.

Conversely, if the interchangeable lens unit 2 is not compatible withmoving picture photography, the body microcomputer 10 deactivates themoving picture photography function (S16). Specifically, even if themoving picture photography mode has been selected with the modeswitching dial 26, the body microcomputer 10 gives priority to adetermination based on lens information, and restricts switching to themoving picture photography mode. In other words, even if controlinformation related to moving picture photography is inputted, thecamera system 1 will be in a state in which a moving picture cannot becaptured. The fact that the mounted interchangeable lens unit 2 is notcompatible with moving picture photography is also displayed on thedisplay unit 20 (S17). Or, the fact that the interchangeable lens unit 2is not compatible with moving picture photography may be displayed whenthe moving picture photography button 35 is pressed.

As discussed above, when the interchangeable lens unit 2 is attached,the camera body 3 determines whether or not moving picture photographyis possible on the basis of lens information stored in theinterchangeable lens unit 2. If the interchangeable lens unit 2 is notcompatible with moving picture photography, then when theinterchangeable lens unit 2 is attached to the camera body 3, theoperating mode automatically switches to moving picture photographymode. This enhances convenience of moving picture photography.

2.7: External Monitor Detection Processing

Next, the operation of the camera system 1 when it is determined whetheror not AV output is possible will be described through reference toFIGS. 13 and 14, for when the user outputs video and audio to anexternal monitor 101 (external monitor detection processing). FIG. 13 isa flowchart of external monitor detection processing, and FIG. 14 is adiagram of when the camera system 1 is connected to the external monitor101 via the AV cable 100.

As shown in FIG. 13, the body microcomputer 10 of the camera body 3determines whether or not the camera body 3 is connected to the externalmonitor 101 (S21). More specifically, the body microcomputer 10 monitorsthe voltage level at the input terminal of an AV cable connectiondetecting circuit 97. As discussed above, when the AV cable 100 isconnected to the AV output terminal 98, the voltage level drops at theinput terminal of the AV cable connection detecting circuit 97. Thus,the body microcomputer 10 determines whether or not the AV cable 100 isconnected to the AV output terminal 98. If it is determined that thecamera body 3 is connected to an external monitor, then it is determinedwhether or not the interchangeable lens unit 2 is compatible with movingpicture photography (S22). If the interchangeable lens unit 2 is notcompatible with moving picture photography, a message to the effect thatit is not compatible with moving picture photography is displayed on thedisplay unit 20, and the external monitor detection processing is ended.

If the interchangeable lens unit 2 is compatible with moving picturephotography, the body microcomputer 10 determines whether or not thecurrent photography mode is the monitor photography mode (S23). If thephotography mode is not the monitor photography mode, the quick returnmirror controller 36 automatically retracts the quick return mirror 23out of the optical path on the basis of a command from the bodymicrocomputer 10 (S24).

It is also possible to determine whether or not the photography mode isthe monitor photography mode by checking the status of the quick returnmirror 23. Since the status of the quick return mirror 23 is switched bythe quick return mirror controller 36 on the basis of a command from thebody microcomputer 10, the body microcomputer 10 can ascertain thestatus of the quick return mirror 23 if the previous command has beenstored ahead of time in the body microcomputer 10.

Meanwhile, if the photography mode is already the monitor photographymode, the quick return mirror 23 is already disposed outside the opticalpath, so step S24 is skipped.

Once the retraction of the quick return mirror 23 is complete, the bodymicrocomputer 10 automatically switches the focus method to a contrastdetection method, and the operating mode changes to the moving picturephotography mode (S25). When the change to moving picture photographymode is complete, the body microcomputer 10 activates the video signaloutput circuit 99 (S26), and video and audio are outputted to theexternal monitor 101 through the AV cable 100 connected to the AV outputterminal 98.

As discussed above, the camera body 3 automatically confirms that the AVcable 100 is attached, and retracts the quick return mirror 23 out ofthe optical path, thereby changing the optical path to the movingpicture photography mode. Therefore, when the AV cable 100 is connected,the moving picture being captured can be instantly viewed by the user onthe external monitor 101, without any special operation being performed.

Furthermore, the means for connecting the camera body 3 to the externalmonitor 101 is not limited to the AV cable 100, and a wireless LAN (notshown), for example, may be used to connect the camera body 3 to theexternal monitor 101. Specifically, a state in which the camera body 3is connected to the external monitor 101 can be rephrased as a state inwhich it is possible to transmit images from the camera body 3 to theexternal monitor 101. If the connection is by wireless LAN, then it maybe determined whether or not the camera body 3 is connected to anexternal monitor by detecting that the wireless LAN function provided tothe camera system 1 has been activated. The configuration may be suchthat the optical path automatically changes to the moving picturephotography mode when the wireless LAN function is activated. Also, itmay be determined whether or not the camera body 3 is connected to theexternal monitor 101 by detecting that wireless communication betweenthe camera body 3 and the external monitor 101 has begun properly.

When video and audio are being outputted to the external monitor 101, amoving picture photography menu may be separately displayed on thedisplay unit 20 provided to the camera system 1. More specifically, theconfiguration may be such that the frame rate during moving picturephotography or the recording pixel count, for example, can be selectedon the display unit 20.

Also, the configuration may be such that if the interchangeable lensunit 2 has not been attached to the camera body 3, the operating modeautomatically changes to the reproduction mode when the AV cable 100 isconnected to the camera body 3. In this reproduction mode, theactivation of the video signal output circuit 99 is switched by the bodymicrocomputer 10, and the desired video and audio or still picturerecorded to the image recorder 18 is outputted to the external monitor101 through the AV cable 100 connected to the AV output terminal 98. Asa result, the moving or still picture recorded to the image recorder 18can be displayed as a visible image on the external monitor 101. Thus,even with the camera body 3 alone, an image can be reproduced byconnecting the external monitor 101 to the camera body 3, which makesthe camera system 1 even more convenient to use.

2.8: Display Unit Detection Processing

Next, the operation of the camera system 1 when the user opens thedisplay unit 20 (display unit detection processing) will be describedthrough reference to FIGS. 15 and 16. FIG. 15 is a flowchart of displayunit detection processing, and FIG. 16 is a diagram of the state ofimaging when the display unit 20 has been opened.

As shown in FIG. 15, the body microcomputer 10 of the camera body 3determines whether or not the display unit 20 has been opened (S31). Ifit is determined that the display unit 20 has been opened, the bodymicrocomputer 10 determines whether or not the interchangeable lens unit2 is compatible with moving picture photography (S32). If theinterchangeable lens unit 2 is not compatible with moving picturephotography, a message to the effect that it is not compatible withmoving picture photography is displayed on the display unit 20 (S36),and the flow is ended.

If the interchangeable lens unit 2 is compatible with moving picturephotography, the body microcomputer 10 determines whether or not thecurrent photography mode is the monitor photography mode (S33). If thephotography mode is not the monitor photography mode, the quick returnmirror 23 is automatically flipped up and out of the optical path (S34).

Just as with the external monitor detection processing discussed above,it is possible to determine whether or not the photography mode is themonitor photography mode by checking the status of the quick returnmirror 23. Since the status of the quick return mirror 23 is switched bythe quick return mirror controller 36 on the basis of a command from thebody microcomputer 10, the body microcomputer 10 can ascertain thestatus of the quick return mirror 23 if the previous command has beenstored ahead of time in the body microcomputer 10.

Meanwhile, if the photography mode is already the monitor photographymode, the quick return mirror 23 is already disposed out of the opticalpath, so step S34 is skipped.

Once the retraction of the quick return mirror 23 is complete, the bodymicrocomputer 10 automatically switches the focus method to a contrastdetection method, and the operating mode changes to the moving picturephotography mode (S35).

Regardless of what the operating mode is, when the display unit 20 hasbeen opened, with this camera body 3 it is possible for the quick returnmirror 23 to be automatically retracted from the optical path, and theoperating mode to be automatically changed to the moving picturephotography mode. Accordingly, moving picture photography can be startedinstantly, without any special operation being performed.

2.9: Self-Timer Determination Processing

Self-timer determination processing will now be described throughreference to FIG. 18. FIG. 18 is a flowchart of self-timer determinationprocessing.

With this camera system 1, the quick return mirror 23 is automaticallyretracted out of the optical path in conjunction with the operation ofthe self-timer function setting button 95. More specifically, as shownin FIG. 18, the body microcomputer 10 of the camera body 3 determineswhether or not the self-timer function setting button 95 has beenswitched on (S41). If the self-timer function setting button 95 has beenswitched on, the body microcomputer 10 determines whether or not thecurrent photography mode is the monitor photography mode (S43). If thephotography mode is not the monitor photography mode, the quick returnmirror 23 is automatically flipped up and out of the optical path (S44).

Meanwhile, if the photography mode is already the monitor photographymode, the quick return mirror 23 is already disposed outside the opticalpath, so step S44 is skipped. When the photography mode changes to themonitor photography mode, a real-time image of the subject is displayedon the display unit 20.

As discussed above, regardless of what the photography mode is, thequick return mirror 23 is automatically retracted out of the opticalpath in conjunction with the operation of the self-timer functionsetting button 95. Accordingly, when the self-timer function isutilized, the user can view the subject on the display unit 20 withoutperforming any special operation, which makes the camera system 1 moreconvenient to use.

2.9: Zooming and Focusing

The operation of the interchangeable lens unit 2 when the user performszooming and focusing will now be described.

As shown in FIG. 17, when the user turns the zoom ring 64, this turningmotion is transmitted to the first rotary frame 53 linked to the zoomring 64. When the first rotary frame 53 rotates around the optical axisAZ, the first rotary frame 53 is guided by the cam though-grooves 50 bof the fixed frame 50, and the first rotary frame 53 moves in the Z axisdirection while rotating around the optical axis AZ. Also, the firstlinear frame 52 rotates with respect to the first rotary frame 53(without rotating with respect to the fixed frame 50), while movinglinearly in the Z axis direction integrally with the first rotary frame53.

When the first rotary frame 53 rotates around the optical axis AZ, thecam pins 54 a are guided by the through-cam groove 53 a, and the firstholder 54 and the first lens support frame 57 fixed to the first holder54 move linearly in the Z axis direction. Also, when the first rotaryframe 53 rotates around the optical axis AZ, the cam pins 61 a areguided by the through-cam grooves 53 b, and the second holder 61 and thesecond lens support frame 58 move integrally and linearly in the Z axisdirection. That is, the focus lens unit 78 moves in the Z axisdirection.

When the first rotary frame 53 rotates around the optical axis AZ, thecam pins 59 a are guided by the linear through-grooves 50 a, and as thesecond rotary frame 55 rotates around the optical axis AZ, it moves in adirection along the optical axis AZ.

When the second rotary frame 55 rotates around the optical axis AZ, thecam pins 59 a are guided by the linear through-grooves 50 a, and thethird lens support frame 59 moves in a direction parallel to the opticalaxis AZ. Also, when the third lens support frame 59 rotates around theoptical axis AZ, the cam pins 60 a are guided by cam grooves 60 b, andthe fourth lens support frame 60 moves in a direction along the opticalaxis AZ.

Thus, by turning the zoom ring 64 toward the telephoto side, it ispossible to move the various lens groups L1 to L4 in a direction alongthe optical axis AZ, from the wide angle end state shown in FIG. 4 tothe telephoto end state shown in FIG. 5, and capture an image at aspecific zoom position.

Here, the focus lens unit 78 moves in a direction along the optical axisAZ as the zoom ring 64 rotates, a contrast detection is performed on thebasis of the output of the imaging sensor 11, and the second lens groupL2 is driven by the ultrasonic actuator unit 80 on the basis of thedetection result. Therefore, the focal state is maintained at a specificsubject distance (for example, infinity) even if the focal lengthchanges from the wide angle end to the telephoto end, or conversely fromthe telephoto end to the wide angle end. In other words, when the zoomring 64 is turned, the focus lens unit 78 moves in the Z axis directionalong with the movement of the first rotary frame 53 and first linearframe 52, and only the second lens group L2 is electrically driven bythe ultrasonic actuator unit 80 in the focus lens unit 78 so that theoptimal focal state will be obtained. The operation of the ultrasonicactuator unit 80 is electrically controlled on the basis of a trackingtable stored ahead of time in the interchangeable lens unit 2. Thistracking table is stored ahead of time in the memory 44 in the lensmicrocomputer 40. More specifically, the relationship betweeninformation about the rotational position of the zoom ring 64 andinformation about the position of the second lens group L2 referenced tothe lens mount 79 in the Z axis direction in the interchangeable lensunit 2 is stored in the memory 44 as table information for each subjectdistance. For instance, tracking information is stored for subjectdistances of 0.3 m, 1 m, and ∞ (infinity). The zoom ring 64 rotationalposition information makes use of the output from the first angledetector 65. For example, in a state of focus at a short distance of 1m, whether the system is changed from the wide angle end to thetelephoto end, or conversely from the telephoto end to the wide angleend, the focal state will be maintained at a short distance byelectrical drive of the second lens group L2 by the ultrasonic actuatorunit 80 on the basis of the tracking table, so the zooming operation canbe carried out smoothly.

When the user turns the focus ring 67, the second angle detector 68detects the rotational angle, and outputs a signal corresponding to thisrotational angle. The lens microcomputer 40 produces a drive signal fordriving the ultrasonic actuator unit 80 on the basis of the focus ringrotational angle signal. This drive signal causes the ultrasonicactuator unit 80 to move in the Z axis direction, so the second lenssupport frame 58 to which the ultrasonic actuator unit 80 is fixed alsomoves in the Z axis direction. In the wide angle end state shown in FIG.4, the second lens group L2 is in a position where the distance to thesubject is infinity, but as the distance to the subject is shortened,the second lens group L2 moves to the Z axis direction positive side.Similarly, in the telephoto end state shown in FIG. 5, the second lensgroup L2 is in a position where the distance to the subject is infinity,but as the distance to the subject is shortened, the second lens groupL2 moves to the Z axis direction positive side. In this case, the amountof movement of the second lens group L2 is greater than in the case ofthe wide angle end.

The focus lens group drive controller 41 is able to receive signals fromthe second angle detector 68, and is able to transmit signals to theultrasonic actuator unit 80. The focus lens group drive controller 41sends the determination result to the lens microcomputer 40. The focuslens group drive controller 41 also drives the ultrasonic actuator unit80 on the basis of a control signal from the lens microcomputer 40.

2.10: Focusing Operation

The focusing operation of the camera system 1 will now be described. Thecamera system 1 has two focus modes: an autofocus photography mode and amanual photography mode.

The user sets the desired photography mode by using the auto photographymode or manual photography mode setting button (not shown) provided tothe camera body 3 or the interchangeable lens unit 2.

In auto photography mode, the lens microcomputer 40 sends a controlsignal to the focus lens group drive controller 41 according tooperation of the moving picture photography button 35 or to the releasebutton 30 being pressed half-way down, drives the ultrasonic actuatorunit 80, and nudges the second lens group L2. The body microcomputer 10sends a command to the digital signal processor 15. The digital signalprocessor 15 sends an image signal at a specific timing to the bodymicrocomputer 10 on the basis of the received command. The bodymicrocomputer 10 computes the amount of movement along the optical axisAZ of the second lens group L2 that will result in the imaging opticalsystem L being in a focused state on the basis of the received imagesignal and focal length information received ahead of time from the zoomring unit 63. The body microcomputer 10 produces a control signal on thebasis of the computation result. The body microcomputer 10 sends thiscontrol signal to the focus lens group drive controller 41.

The focus lens group drive controller 41 produces a drive signal fordriving the ultrasonic actuator unit 80 on the basis of the controlsignal from the body microcomputer 10. The ultrasonic actuator unit 80is driven on the basis of this drive signal. Drive of the ultrasonicactuator unit 80 moves the second lens group L2 automatically in the Zaxis direction.

As discussed above, focusing is carried out by the autofocus photographymode of the interchangeable lens unit 2 or the camera body 3. The aboveoperation is executed instantly after the user presses the releasebutton 30 half-way down, or presses the moving picture photographybutton 35. If the user presses the release button 30 all the way down,or presses the moving picture photography button 35, the bodymicrocomputer 10 executes imaging processing, and when this imaging iscomplete, a control signal is sent to the image recording controller 19.The image recorder 18 records the image signal to an internal memoryand/or removable memory on the basis of a command from the imagerecording controller 19. The image recorder 18 records information tothe effect that the photography mode is the autofocus photography mode,along with the image signal, to an internal memory and/or removablememory on the basis of a command from the image recording controller 19.

On the other hand, in manual focus photography mode, the lensmicrocomputer 40 asks the focus lens group drive controller 41 forinformation about the rotational angle of the focus ring unit 66. Thelens microcomputer 40 produces a control signal for moving the secondlens group L2 on the basis of a detection value obtained from therotational angle of the focus ring 67. The lens microcomputer 40 sendsthe control signal thus produced to the focus lens group drivecontroller 41.

The focus lens group drive controller 41 produces a drive signal fordriving the ultrasonic actuator unit 80 on the basis of the controlsignal from the lens microcomputer 40. The ultrasonic actuator unit 80is driven on the basis of this drive signal. Drive of the ultrasonicactuator unit 80 moves the second lens group L2 according to the amountand direction of rotation of the focus ring 67.

As discussed above, focusing is carried out by the manual focusphotography mode of the camera system 1. In manual focusing mode,imaging is performed in the same state when the user presses the releasebutton 30 all the way down, or presses the moving picture photographybutton 35.

Upon completion of the imaging, the body microcomputer 10 sends acontrol signal to the image recording controller 19. The image recorder18 records the image signal to an internal memory and/or removablememory on the basis of a command from the image recording controller 19.The image recorder 18 records information to the effect that thephotography mode is the manual focus photography mode, along with theimage signal, to an internal memory and/or removable memory on the basisof a command from the image recording controller 19.

3. Features of Camera System

The camera system 1 described above has the following features.

(1) With this camera system 1, when the interchangeable lens unit 2 ismounted to the camera body 3, the body microcomputer 10 determineswhether or not the interchangeable lens unit 2 is compatible with movingpicture photography. If it is determined by the body microcomputer 10that the interchangeable lens unit is compatible with moving picturephotography, the quick return mirror controller 36 retracts the quickreturn mirror 23 out of the optical path of the imaging optical systemL. That is, when an interchangeable lens unit 2 compatible with movingpicture photography is mounted to the camera body 3, the quick returnmirror 23 is automatically retracted out of the optical path, and theoperating mode is automatically switched to the moving picturephotography mode. Accordingly, there is no need for any operation forswitching to the moving picture photography mode after the mounting ofthe interchangeable lens unit 2, and this makes the camera system 1 moreconvenient to use.

In particular, when the interchangeable lens unit 2 is a moving picturephotography-dedicated lens that is only compatible with moving picturephotography, there is no need to switch the operating mode to the movingpicture photography mode, which makes the camera system 1 moreconvenient to use.

Also, there are already many interchangeable lens units that are notcompatible with moving picture photography, but with this camera system1, if an interchangeable lens unit that is not compatible with movingpicture photography is mounted to the camera body 3, the bodymicrocomputer 10 deactivates the moving picture photography function, sothe system remains usable. Accordingly, an interchangeable lens unitthat was purchased previously will not go to waste, and this providesthe user with a more useful camera system.

(2) With this camera system 1, when the moving picture photographybutton 35 is pressed, the quick return mirror controller 36 retracts thequick return mirror 23 out of the optical path, and then moving picturephotography is commenced. Therefore, it takes less time until the startof moving picture photography.

(3) With this camera system 1, when the AV cable connection detectingcircuit 97 detects that the external monitor 101 has been connected tothe AV output terminal 98 of the camera body 3, the quick return mirrorcontroller 36 retracts the quick return mirror 23 out of the opticalpath of the optical system. As a result, the user can view the subjecton the external monitor 101 merely by connecting the external monitor101 to the camera body 3. This makes the camera system more convenientto use.

(4) As discussed above, the display unit 20 can be in either a closedstate in which it is disposed parallel to the rear face of the case 3 a,or an open state in which it is disposed tilted and facing upward withrespect to the rear face of the case 3 a. When the user captures animage while viewing the subject on the display unit 20, it isanticipated that the display unit 20 will usually be in its open state.

With this camera system 1, when the display unit 20 is put in an openstate with respect to the case 3 a, the open/closed detection sensor 111detects the change in the position of the display unit 20. On the basisof this detection result, the quick return mirror 23 is automaticallyretracted from the optical path of the imaging optical system L. As aresult, the user can view the subject on the display unit 20 by puttingthe display unit 20 in its open state. Consequently, when the displayunit 20 is opened and moving picture photography is performed, there isno need to switch the optical path to the moving picture photographymode, and this makes the camera system 1 more convenient to use.

(5) When the self-timer function is used to capture an image, since thecamera system 1 itself is placed somewhere by the user, in this case itis preferable to view the subject on the display unit 20.

With this camera system 1, when the self-timer function setting button95 is pressed, the quick return mirror 23 is automatically retracted outof the optical path of the optical system. Therefore, when theself-timer function is used for image capture, there is no need toswitch the optical path to the monitor photography mode, and this makesthe camera system 1 more convenient to use.

(6) With this camera system 1, if the interchangeable lens unit 2 is notcompatible with moving picture photography, a message to that effectwill be displayed on the display unit 20, so the user can find out thatthe interchangeable lens unit 2 is not compatible with moving picturephotography merely by mounting the interchangeable lens unit 2 to thecamera body 3. The user can also check whether or not theinterchangeable lens unit is compatible with moving picture photography,by mounting the interchangeable lens unit 2 to the camera body 3.

Other Embodiments

The single lens reflex camera, camera body, and interchangeable lenspertaining to the present invention are not limited to the embodimentgiven above, and various modifications and changes are possible withoutdeparting from the gist of the invention.

Furthermore, components that have substantially the same function as inthe above embodiment will be numbered the same, and not described indetail again.

(1) In the above embodiment, if the interchangeable lens unit 2 is notcompatible with moving picture photography, the quick return mirror 23is automatically retracted out of the optical path when theinterchangeable lens unit 2 is mounted to the camera body 3.

However, the camera system 1 need not have a constitution in which thequick return mirror 23 is automatically retracted out of the opticalpath upon the mounting of the interchangeable lens unit 2, and theconvenience of the camera system can still be enhanced.

For example, as shown in FIG. 13, the convenience of the camera system 1can be enhanced if the constitution is such that the quick return mirror23 is automatically retracted out of the optical path when the externalmonitor 101 is connected to the camera body 3 via the AV cable 100.

Similarly, as shown in FIG. 15, the convenience of the camera system 1can be enhanced if the constitution is such that the quick return mirror23 is automatically retracted out of the optical path of the imagingoptical system L on the basis of the detection result of the open/closeddetection sensor 111.

Furthermore, as shown in FIG. 18, if the constitution is such that thequick return mirror 23 is automatically retracted out of the opticalpath when the mode is set to self-timer photography mode with theself-timer function setting button 95, then the user can view thesubject on the display unit 20 without any extra operation whencapturing an image with the self-timer function. Here again, theconvenience of the camera system 1 can be enhanced.

(2) In the above embodiment, if a remote control switch is connected tothe camera body 3, then moving picture photography can be performedusing a tripod, and more particularly, in low-angle photography in whichthe display unit 20 is used in its open state. In this case, when it isdetected that the remote control switch is connected to the camera body3, the quick return mirror 23 may be automatically retracted out of theoptical path and the mode changed to monitor photography mode. In thiscase, the convenience of the camera system can be further enhancedbecause using the remote control switch allows the user to performlow-angle photography while looking at a live view image with thedisplay unit 20 in its open state.

(3) In the above embodiment, the focal length is manually adjusted witha zoom ring, but there is no need to limit to this, and an electroniczoom may be used instead.

(4) In the above embodiment, the various setting menus for movingpicture photography can be set using the display unit on the basis ofwhether or not moving picture photography is possible with theinterchangeable lens unit.

(5) In the above embodiment, an ultrasonic actuator is used as theactuator for focusing, but this may be another actuator that allows thefocus lens group to be directly driven, such as a stepping motor.

(6) In the above embodiment, the focus lens group was the second lensgroup L2, but there is no need to limit to this, and it may instead bethe third lens group L3, the fourth lens group L4, or another lensgroup. Also, a case was described in which there was only one secondlens group L2 as the focus lens group, but a plurality of lens groupsmay work together to constitute an optical system that performsfocusing.

(7) In the above embodiment, an image blur correction unit may beprovided to the interchangeable lens unit 2, to the camera body 3, or toboth. If to both, the camera system may be such that either image blurcorrection unit can be selected.

(8) In the above embodiment, if the shutter drive motor 32 isconstituted by an independent motor, a silent mode may be provided inthe monitor photography mode. Specifically, if the user sets the silentmode, then when there is an automatic change to the monitor photographymode, the operation of the quick return mirror 23 will make no noisewhen the release button 30 is pressed. Accordingly, photography will bepossible even in quiet surroundings, without worry about noise from thequick return mirror 23.

Also, when the image blur correction unit is operated, photography inthe monitor photography mode will prevent the impact caused by operationof the quick return mirror 23 from adversely affecting the image blurcorrection unit, so the effect thereof is better.

(9) In the above embodiment, the exposure time of the imaging sensor iscontrolled by operating the shutter unit, but there is no need to limitto this, and the exposure time of the imaging sensor may instead becontrolled by an electronic shutter or the like.

(10) In the above embodiment, the lens information includes informationabout whether or not there is compatible with moving picturephotography. However, whether or not there is compatibility with movingpicture photography may be determined from whether or not the drivesystem of the second lens group L2 (focus lens group), or the focus lensgroup drive controller 41 or the like is compatible with a contrastdetection method.

(11) In the above embodiment, the interchangeable lens unit 2 iscompatible with moving picture photography, but there may be cases inwhich only the camera body 3 is compatible with moving picturephotography and the interchangeable lens unit 2 is not compatible withmoving picture photography.

(12) In the flowchart of FIG. 12, after the moving picture photographyfunction is activated in step S14, the quick return mirror 23 isretracted out of the optical path in step S15. However, the order ofsteps S14 and S15 may be reversed.

(13) In the above embodiment, video and audio are outputted from thecamera body 3 to the external monitor 101, but the constitution may besuch that only video is outputted.

1. A camera body used in a camera system along with an interchangeablelens unit having an optical system configured to form an optical imageof a subject, said camera body comprising: an imaging unit configured toconvert the optical image into an image signal and acquire an image ofthe subject; a movable reflecting mirror configured to be in a firststate of being positioned in an optical path of the optical system andin a second state of being positioned outside of the optical path; and amirror controller configured to retract the reflecting mirror out of theoptical path of the optical system when the reflecting mirror is in thefirst state of being in the optical path of the optical system and amoving picture photography mode is selected, the moving picturephotography mode being a mode for capturing moving pictures.
 2. Thecamera body according to claim 1, further comprising a display unitconfigured to display a real-time image acquired by the imaging unit inthe moving picture photography mode and in the second state in which thereflecting mirror is retracted out of the optical path of the opticalsystem.
 3. The camera body according to claim 2, wherein the recordingof a moving picture is commenced when a moving picture recording startcontrol is operated in the moving picture photography mode and in thesecond state in which the reflecting mirror is retracted out of theoptical path of the optical system.
 4. A camera system, comprising: anoptical system configured to form an optical image of a subject; animaging unit configured to convert the optical image into an imagesignal and acquire an image of the subject; a movable reflecting mirrorconfigured to be in a first state of being positioned in an optical pathof the optical system and in a second state of being positioned outsideof the optical path; and a mirror controller configured to retract thereflecting mirror out of the optical path of the optical system when thereflecting mirror is in the first state of being in the optical path ofthe optical system and a moving picture photography mode is selected,the moving picture photography mode being a mode for capturing movingpictures.
 5. The camera system according to claim 4, further comprisinga display unit configured to display a real-time image acquired by theimaging unit in the moving picture photography mode and in the secondstate in which the reflecting mirror is retracted out of the opticalpath of the optical system.
 6. The camera system according to claim 5,wherein the recording of a moving picture is commenced when a movingpicture recording start control is operated in the moving picturephotography mode and in the second state in which the reflecting mirroris retracted out of the optical path of the optical system.